docs: def expand_node_successors(universe, graph, node: BaseEntity) -> None:
      """Expand around the successors of the given node in the result graph.
  
      :param pybel.BELGraph universe: The graph containing the stuff to add
      :param pybel.BELGraph graph: The graph to add stuff to
      :param node: A BEL node
      """
      skip_predecessors = set()
      for predecessor in universe.predecessors(node):
          if predecessor in graph:
              skip_predecessors.add(predecessor)
              continue
  
          graph.add_node(predecessor, **universe.nodes[predecessor])
  
      graph.add_edges_from(
          (predecessor, target, key, data)
          for predecessor, target, key, data in universe.in_edges(node, data=True, keys=True)
          if predecessor not in skip_predecessors
      )
  
      update_node_helper(universe, graph)
      update_metadata(universe, graph)